Circuit breaker and similar switch apparatus for electric power current lines



July 15, 1930. o. JACOBSON ET AL CIRCUIT BREAKER AND SIMILAR SWITCH APPARATUS FOR ELECTRIC POWER CURRENT LINES Filed Jan. 9, 1928 2 Sheets-Sheet 1 o0 EL .9 i E A H Um Lg r.

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Patented July 15, 1930 UNITED STATES PATENT OFFICE.

L0]! JACOBSON AND ARE OSKAR GYLLING, OF STOCKHOLM, SWEDEN CIRCUIT BREAKER AND SIMILAR SWITCH APPARATUS FOR ELECTRIC POWER CURRENT LIN ES Application filed January 9, 1928, Serial No. 245,320, and in Sweden Ian-uaryvm, 1927.

The present invention relates to an improvement in circuit-breakers and slmilar switch apparatus for electric power current lines. In order to provide against accldents occurring through involuntary coming 1n contact with the live parts of such switch aparatus it is customary to place the same in boxes or houses, the door of which is provided with a locking device which is connected with the switch apparatus in such manner that the door can only be opened when the switch apparatus is open. In splte of such protective measures, however, the danger of accidents occurring is still great. For economical as well as-acsthetic reasons such houses are built as small as possible, and therefore, since part of the contact members of the switch apparatus are still live also when the switch apparatus has been opened, the risk of the operators involuntarily coming in contact with live parts when working in the narrow house. is still great.

Now, the purpose of the improvement which forms the subject of the present invention, is to avoid this difiiculty. For this pur pose the invention consists principally in that adjacent those stationary contact members of the switch apparatus which are still live when the switch apparatus is open, one or more protecting caps or the like are pivotally mounted, which are connected to the movable contact members of the switch apparatus in such manner that with the switch apparatus open said cap or caps shield off or enclose said live contact members, but upon the movable contact members being moved towards the stationary contact members for the purpose of closing the switch apparatus, said cap or caps are moved aside so that the switch apparatus may be closed. and also to the locking device of the door in such manner that the door may be opened only when, with the switch apparatus opened, said protecting cap or caps shield off or enclose the contact members then still live. In this manner the possibility of coming in contact with the live members is precluded in a fully automatic and efficient manner. The protecting cap or caps should, of course, preferably be connected to ground so that they can not carry any dangerous tension.

In the accompanying drawings an embodiment of the invention is illustrated by Way of example. Fig. 1 shows a switch arranged according to the invention and mounted in a house, 1n front view and in closed position, the house itself being shown in section. Fig. 2 shows the same switch in side view and in closed position, Fig. 3 shows the same viewed from t e side and in partially opened position, and Fi 4 shows the same viewed from the side and in fully opened position. Finally, Fig. 5 shows the locking device for the door of the house, viewed from above.

The switch is mounted in a house 1 which is provided at one side with a door 3 movable on hinges 2. The switch illustrated is a triple pole switch, and consists of three upper stationary contact members 4 which are formed in the usual way as spring jaws and are supported, through the agency of insulators 5, by a plate 6 secured by means of suitable stays 7 to the rear wall of the house 1, and of three lower stationary contact members 8 which are supported, through the agency of insulators 9, by a frame 10 of angle irons rigidly attached to the plate 6, and of three movable contact members 11 which, in the instance illustrated, are assumed to be made in the shape of knives and are attached to the upper ends of three porcelain tubes 12 which are pivotally connected at their lower ends by means of metal clamps 13 to the lower stationary contact members 8. so that said tubes 12 may be swung from the closed position shown in Fig. 2 to the open position shown in Fig. 4. The three porcelain tubes 12 which are provided in the usual manner with flanges 14 in order to prevent flash-overs along the outer surfaces of the tubes, are rigidly connected to one another by means of two clamping bars 15, so that all tubes are forced to move in unison. The tubes 12 each contain a fine fuse wire which electrically connects the contact member 11 secured to the upper end of the tube to the metal clamp 13 at the lower end of the tube, so that the switch forms simultaneously a safety device. When the switch occupies the closed position shown in Figs. 1 and 2, the stationary contact members 4 of the upper row which are connected to the conductors of the high tension cable 16 and, therefore, are always live, are thus electrically connected to the corresponding contact members 8 of the lower row which, in the instance illustrated, are assumed to be connected to the high tension terminals 17 of a transformer.

The closing and opening of the switch is effected in the instance illustrated, by turning a shaft 18 which is rotatably journalled in two bearings 19 secured to the frame 10, and in one side wall of the house 1 through which one end of the shaft 18 extends. Secured to the end of the shaft 18 projecting outside the wall of the house are a disk 20 and a lever 21 which latter serves for turning the shaft 18 and thus also for closing and opening the switch. For this purpose there are secured to the shaft 18 inside the house two arms 22 which are connected by means of short links 23 to the inner clamping bar 15, as shown in Fig. 4, and thus to the three porcelain tubes 12, and also pivotally connected, by means of longer links 24, to a sheet metal cap 25 having an approximately semicircular cross section, which, when the switch is in open position, serves to shield or enclose those three stationary contact members 4 which are always live, and which for this purpose is pivotally mounted on the upper end of the frame 10 by means of pivots 26. The disk 20 secured to the shaft 18 is provided at one point of its circumference with a radial slot 27 which is adapted to cooperate with a semicircular extension 28 on an angle iron bar 29 secured to the outside of the door 3, in such manner that the door 3 can only be opened when the switch occupies the fully opened position illustrated in Fig. 4, since only in this position of the switch and the corresponding position of the shaft 18 the slot 27 is in register with the extension 28, so that, when the door 3 is being opened, in the direction of the arrow in Fig. 5, the extension can pass through the slot 27 and through a slot 30 in the wall of the house then located opposite the first named slot. On the other hand, when the switch occupies the positions shown in Figs. 2 and 3, the slot 27 occupies a position to one side of the extension 28. so that. if an attempt is made to open the door 3, said extension will strike against the disk 20, see Fig. 5, which latter will thus prevent opening of the door.

As will be seen from the above description and from the drawings, the protecting cap 25 rotatable on the pivots 26, is connected through the links 24 and 23 to the movable contact members 11 of the switch, in such manner that when the switch is open, Fig. 4, the cap 25 completely encloses the stationary contact members 4 which are still live, so that there is no risk of involuntarily touching said contact members. When, with the aid of the lever 21, the movable contact members 11 are moved towards the stationary contact members 4 for closing the switch, however, the protecting cap 25 is moved upwards out of the way, see Fig. 2, so that the switch may be closed without the protecting cap being in the way. The locking device 28,20 for the door 3 of the house is also connected through the parts 18, 22, 23 with the movable contact members 11, and through the links 24 also with the protecting cap 25, in such manner that the door 3 can be opened only when the switch is open and the protecting cap encloses the stationary contact members 4, which are always live. The described arrangement thus precludes in a very efficient manner involuntary contact with the live contact members l.

As shown in Fig. 2, in the closed position of the switch the arms 22 and links 24 which effect the turning movement of the protecting cap, are approximately in alignment, while in said position of the parts the arms 22 form an angle slightly less than 90 to the links 23 which effect the turning movement of the porcelain tubes 12 and movable contact members 11. By this arrangement the result is attained that, when turning the shaft 18 and arms 22 in the counter-clockwise direction in F ig. 2 for opening the switch, the movement of the cap 25 becomes very small while the movement of the contact members 11 becomes large during the first. part of the turning movement, so that, as will be seen from Fig. 3, the cap 25 retains its raised position practically unchanged, until the members 11 have moved entirely out of contact with the live members 4. On the other hand. when the switch is again closed by turning the shaft 18 in the clockwise direction from the position shown in Fig. 4, the movement of the cap 25 becomes large while the movement of the contact members 11 becomes small during the first part of the turning movement of the shaft 18. In this manner the movable contact members 11 and the protecting cap 25 are thus always held at the proper distance 1 from each other.

The lever 21 serving for operating the switch, is arranged-in such manner that by means of a padlock 31 it may be locked to the bar 29 in the position shown in Fig. 2, when the switch is closed, and also to an ear 32 secured to the outside of the wall of the house, in the position shown in Fig. 4, when the switch is open. In this manner unauthorized persons are prevented from operating the switch and from moving the protecting cap 25 out of its position. for instance when a lineman is in the house for performing some work on the switch.

The embodiment above described and illustrated in the drawing is only to be regarded as an example and may, of course, be modified in respect of its details in several ways without departing from the principle of the invention. Thus, the pivotally mounted protecting cap illustrated may, for instance, be replaced by a slidably mounted shieldwhich, upon the switch opening, is moved in front 0 the still live contact members. If for local reasons it is not suitable to place the door in one side wall of the house and it must, instead, be placed in the front wall, the shaft- 18 may be connected to the operating lever provided outside the house, for instance, by means of a bevel gearing.

We claim:

1. In a switch apparatus for electric power current lines of the character described, the combination of a switch comprising stationary contact members connected to the power line, a plate supporting said stationary contact members and movable contact members pivotally mounted, a house in which said switch is mounted,,,a/door on said house, a locking device for said door, at least one protecting cap pivotally mounted adjacent-said stationary contact members and movable against said plate to enclose said contact members between said cap and said plate, an

operating shaft rotatably mounted, arms on said shaft, links connecting said arms with said protecting cap and with said'movable contact members in such manner that when said switch is open said cap encloses said sta-- such turning movement of said shaft and that upon said shaft turning for closing said switch themovement of said cap becomes large while the-movement of said movable contacts becomes small during the first part of such turning movement of said shaft, and means connecting said protecting cap to said locking device in such manner that said door can only be openend when said switch is open and said cap shields off said stationary contact members.

2. In a switch apparatus for electric power current lines of the character described, the combination. of a switch comprising stationary contact members connected to the power line, a plate supporting said stationary contact members and movable contact members pivotally mounted, a house in which said switch is mounted, a door on said house, a

locking device for said door, at least one prosaid protecting cap and with said movable contact members in such manner that when said switch is open said cap encloses said stationary contact members but is moved aside upon said movable contact members moving towards said stationary contact members for closing the switch, said shaft having one end projecting through the wall of said house ad acent said door, said door having a projection, and a disk secured to said projecting end of said shaft and havin a slot adapted in the position of said sha t corresponding to fully open position of said switch to register with said projection on said door so as to allow said projection to pass through said slot and thus said door to open only when 1 said switch is fully open and said cap shields off said stationary contact members.

3. In a switch apparatus for electric power current lines of the character described, the combination of a switch comprisin' stationary contact members connected to t e power line, a plate supporting saidstationary contact members, and movable contact members pivotally mounted, a house in which said switch is mounted, a door on said house, a locking device for said door, at least one protecting cap pivotally mounted adjacent said stationary contact members and movable against said plate to enclose said contact members between said cap and said plate, an operating shaft rotatably mounted, at least one arm on said shaft, *a link connecting said arm with said protecting cap, a second link connecting said arm with said movable contactmembers, said movable contact members,

cap, links, arm, and shaft having such relative positions that in the open position ofsaid switch said arm is substantially in alignment with said second link but is at substantially right angles to said first mentioned link and said cap is closed against said plate and encloses said stationary contact members and in the closed position of said switch said arm is at an angle with said second link but is substantially in alignment with said firstmentioned link and said cap is moved aside from said stationary contact members, so that upon said shaft turning for opening said switch the movement of said cap becomes small while the movement of said movable contact members becomes large during the first part of such turning movement of said shaft and that upon said shaft turningfor' closing said switch the movement of said cap becomes large while the movement of said movable contactsbecomes small durin the first part of such turning movement 0 said shaft, and means connecting said protecting cap to said locking device in such manner that said door can only be opened when said switch is open and said cap encloses said stationary contact members.

4. In a switch apparatus for electric power current lines of the character described, the combination of a switch comprisingl stationary contact members connected to t e power line, a plate supporting said stationary contact members, and movable contact members pivotally mounted, a house in which said switch is mounted, a door on said house, at least one protecting cap pivotally mounted adjacent said stationar contact members and movable against said p ate to enclose said contact members between said cap and said plate, an operating shaft rotatably mounted, at

least one arm on said shaft, a link connecting said arm with said protectin cap, a second link connecting said arm wit said movable cont-act members, said movable contact memhers, cap, links, arm, and shaft having such relative positions that in the open position of said switch said arm is substantially in alignment with said second link but is at substantially right angles to said first-mentioned link and said cap is closed against said plate and encloses said stationary contact members and in the closed position of said switch said arm is at an angle with said second link but is substantially in alignment with said firstmentioned link and said cap is moved aside from said stationary contact members, said shaft having one end projecting through the wall of said house adjacent said door, said door having a projection, and a disk secured to said projecting end of said shaft and having a slot adapted in the position of said shaft corresponding to fully open position of said switch to register with sa1d projection on said door so as to allow said projection to pass through said slot and thus said door to open only when said switch is fully open and said cap encloses said stationar contact members.

OLOF J A OBSON.

AKE OSKAR GYLLING'. 

